/*
 * Copyright (c) 2011, Nikolaus Moll
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * * Neither the name of the gradecalculator.net nor the
 * names of its contributors may be used to endorse or promote products
 * derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 */
package net.gradecalculator.core;

import java.util.LinkedList;
import java.util.List;

import net.gradecalculator.core.interfaces.ICoreFactory;
import net.gradecalculator.core.interfaces.ICourseOfStudiesIdentifier;
import net.gradecalculator.core.interfaces.IModule;
import net.gradecalculator.core.interfaces.IRegulationsItem;
import net.gradecalculator.core.interfaces.IStudyRegulations;
import net.gradecalculator.core.interfaces.IUniversity;
import net.gradecalculator.core.util.CoreServiceProviderUtil;
import net.gradecalculator.core.util.RegulationsPluginUtil;
import net.gradecalculator.core.util.StudentPluginUtil;
import net.gradecalculator.plugin.core.interfaces.IRegulationsPlugin;
import net.gradecalculator.plugin.core.interfaces.IStudentPlugin;

public final class GCCore {
	private static ICoreFactory factory = null;
	private static List<IRegulationsPlugin> regulationPlugins = null;
	private static List<IStudentPlugin> studentPlugins = null;

	private static String applicationRoot = ".";

	private GCCore() {}

	public static void setApplicationRoot(final String directory) {
		applicationRoot = directory;

		if (regulationPlugins != null) {
			for (final IRegulationsPlugin plugin : regulationPlugins) {
				plugin.setApplicationDirectory(applicationRoot);
			}
		}
		if (studentPlugins != null) {
			for (final IStudentPlugin plugin : studentPlugins) {
				plugin.setApplicationDirectory(applicationRoot);
			}
		}
	}

	public static IUniversity readUniversity(final String universityName) {
		for (final IRegulationsPlugin plugin : getReglationsPlugins()) {
			try {
				final IUniversity result = plugin.readUniversity(universityName);
				if (result != null) {
					return result;
				}
			} catch (final Exception e) {
				// ignore
			}
		}

		// TODO throw exception ?
		return null;
	}

	public static IStudyRegulations readRegulations(final ICourseOfStudiesIdentifier identifier) {
		for (final IRegulationsPlugin plugin : getReglationsPlugins()) {
			try {
				final IStudyRegulations result = plugin.readStudyRegulations(identifier);
				if (result != null) {
					return result;
				}
			} catch (final Exception e) {
				// ignore
			}
		}

		// TODO throw exception ?
		return null;
	}

	public static List<IRegulationsPlugin> getReglationsPlugins() {
		if (factory == null) {
			if (getFactory() == null) {
				throw new IllegalStateException("No core factory found.");
			}
		}

		if (regulationPlugins == null) {
			regulationPlugins = RegulationsPluginUtil.getPlugins();
			for (final IRegulationsPlugin plugin : regulationPlugins) {
				plugin.setCoreFactory(factory);
				plugin.setApplicationDirectory(applicationRoot);
			}
		}

		return regulationPlugins;
	}

	public static List<IStudentPlugin> getStudentPlugins() {
		if (factory == null) {
			if (getFactory() == null) {
				throw new IllegalStateException("No core factory found.");
			}
		}

		if (studentPlugins == null) {
			studentPlugins = StudentPluginUtil.getPlugins();
			for (final IStudentPlugin plugin : studentPlugins) {
				plugin.setCoreFactory(factory);
				plugin.setApplicationDirectory(applicationRoot);
			}
		}

		return studentPlugins;
	}

	public static void setFactory(final ICoreFactory factory) {
		GCCore.factory = factory;
		regulationPlugins = null;
	}

	public static ICoreFactory getFactory() {
		if (factory == null) {
			setFactory(CoreServiceProviderUtil.getPlugins().get(0));
		}
		return factory;
	}

	public static List<String> getUniversities() {
		final List<String> result = new LinkedList<String>();

		for (final IRegulationsPlugin plugin : getReglationsPlugins()) {
			try {
				final List<String> pluginList = plugin.getUniversities();
				if ((pluginList == null) || (pluginList.isEmpty())) {
					continue;
				}

				for (final String item : pluginList) {
					if (result.contains(item)) {
						continue;
					}
					result.add(item);
				}
			} catch (final Exception e) {
				// ignore
			}
		}

		return result;
	}

	public static List<String> getDegrees(final String university) {
		final List<String> result = new LinkedList<String>();

		for (final IRegulationsPlugin plugin : getReglationsPlugins()) {
			try {
				final List<String> pluginList = plugin.getDegrees(university);
				if ((pluginList == null) || (pluginList.isEmpty())) {
					continue;
				}

				for (final String item : pluginList) {
					if (result.contains(item)) {
						continue;
					}
					result.add(item);
				}
			} catch (final Exception e) {
				// ignore
			}
		}

		return result;
	}

	public static List<String> getCourses(final String university, final String degree) {
		final List<String> result = new LinkedList<String>();

		for (final IRegulationsPlugin plugin : getReglationsPlugins()) {
			try {
				final List<String> pluginList = plugin.getCourses(university, degree);
				if ((pluginList == null) || (pluginList.isEmpty())) {
					continue;
				}

				for (final String item : pluginList) {
					if (result.contains(item)) {
						continue;
					}
					result.add(item);
				}
			} catch (final Exception e) {
				// ignore
			}
		}

		return result;
	}

	public static List<String> getSemesters(final String university, final String degree, final String course) {
		final List<String> result = new LinkedList<String>();

		for (final IRegulationsPlugin plugin : getReglationsPlugins()) {
			try {
				final List<String> pluginList = plugin.getSemesters(university, degree, course);
				if ((pluginList == null) || (pluginList.isEmpty())) {
					continue;
				}

				for (final String item : pluginList) {
					if (result.contains(item)) {
						continue;
					}
					result.add(item);
				}
			} catch (final Exception e) {
				// ignore
			}
		}

		return result;
	}

	public static IRegulationsItem create(final Class<?> classType) {
		System.out.println(classType);
		System.out.println(" vs " + IModule.class);
		if (classType.equals(IModule.class)) {
			return factory.createModule();
		}

		return null;
	}

}
